<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            background-image: url("img/background.jpeg");
            background-repeat: no-repeat;
            background-position: center top;
            background-attachment: fixed;
        }
        #a1 {
            color: blue;
        }
        .red{
            color: red;
        }
        .font{
            font-size: 20px;
        }

        a:link{
            color: black;
            text-decoration: none;
        }

        a:visited{
            color: aqua;
        }

        a:active{
            color: green;
        }

        input:focus{
            background-color: black;
        }

        #test1{
            width: 200px;
            height: 40px;
            font-size: 14px;
            font-weight: 400;
            line-height: 40px;
            background-image: url("img/icon.png");
            background-repeat: no-repeat;
            background-position: left center;
            text-indent: 1.5em;
        }
    </style>
</head>
<body>
<p id="a1">12345</p>

<div class="red font">abc</div>

<a href="#">google</a>

<input type="text">

<h3 id="test1">成长守护平台</h3>

<div id="father"></div>
<div id="son"></div>
</body>
</html>